modern GPU has automatic OC based on your power and thermal limit.
make sure you have some good airflow in your case, download msi afterbuner and max the power/voltage slider for a easy overclock,
if you want to get higher clock, you can slowly increase memory core frequency at 10 MHz increment (1 ite)m at a time), run furmark or something to monitor thermal and artifact and repeat the process. don't expect the results to be more than 10%. (you don't get 1070 performance from a oc 1060)
you may also use the fan controller to make the cooling scheme more aggressive if the temperature is too high (> 80).